1、蘭州大學碩士學位論文新月形沙丘風場的數(shù)值模擬姓名：江麗娟申請學位級別：碩士專業(yè)：工程力學指導教師：鄭曉靜20090501蘭州大學碩士學位論文AbstractAbstractTherelationshipsamongsandfluxwindflowandtopographyarecomplexandcoupledStudyingflowfieldnearthedunesisusefultounderstandtheprocessandme

2、chanicsofdunesformationAndthereareonlycountablepapersincludingdetailedanalysisaboutflowoveranbarchandune，suchaSflowaccelerationupthestossslopeandwhatinfluencesseparationlengthintheleesideThispapersimulatedflowoveranisola

3、tedbarchandunewithdifferentaSpectrationsbycomputationalfluiddynamics(CFD)softwareInchapter2，WefocusonflowaccelerationupwiththestossslopeForexample，Weanalyzetherelationshipsbetweenspeed—upfactorandduneheight，theangleofthe

4、stossslope，windspeedAndaccordingtotheserelationships，wederivedaformulaofthespeedupfactorInchapter3，WesimulateflowoveranisolatedbarchanduneemployingcommercialsoRwareCFDfromFLUENTInc，anddiscussehowtheduneheightandupwindspe

5、edtoinfluencetheseparationlength，protectionlengthAfterWeanalyzedreverseflowinthelee—side，weproposedthatduneheightplaysaimportantroleinleadingtothemoreextentoftheflowaccelerationTheincrementofwindspeedatthedunecrestincrea

6、SeswithhigherduneAndupwindspeedalsoCaninfluencetheincrementofthewindspeedupthestossslope，butcomparingwiththeroleoftheduneheight，thisincrementissmallSeparationlengthintheleesidealsoincreaseswithduneheightInchapter4，wesimu

7、lateflowfieldarounda3Dbarchandune，andanalyzetherelationshipbetweentheairflowandsandrippleonthedunesurface，andpreliminarilydiscussthedistributionoftheshearstressonthedunesurfaceTheresultsshowthatthereexistsapparentacceler